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INTRO

Section: Misc. Reference Manual Pages (3LIBIIO)
Updated: 19 June 2020
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NAME

libiio-0.21 - introduction to libiio, a library for interacting with the Linux IIO subsystem and devices  

SYNOPSIS

#include <iio.h>

cc file.c -liio  

OPTIONS

The define IIO_CHECK_REG will warn if return values are not checked. Most libiio functions, if/when a failure occurs will return a negative error number. this warning will ensure these error numbers are looked at. There is nothing more frustraining than calling a function, debugging some hardware, and then eventually realizing there was a typo in an attribute name. This option will force libraries users to at least capture the return value.

cc file.c -DIIO_CHECK_REG -liio

 

DESCRIPTION

libiio is a library used to interface to the Linux Industrial Input/Output (IIO) Subsystem. The Linux IIO subsystem is intended to provide support for devices that in some sense are analog to digital or digital to analog converters (ADCs, DACs). This includes, but is not limited to ADCs, Accelerometers, Gyros, IMUs, Capacitance to Digital Converters (CDCs), Pressure Sensors, Color, Light and Proximity Sensors, Temperature Sensors, Magnetometers, DACs, DDS (Direct Digital Synthesis), PLLs (Phase Locked Loops), Variable/Programmable Gain Amplifiers (VGA, PGA), and RF transceivers. You can use libiio natively on an embedded Linux target (local mode), or use libiio to communicate remotely to that same target from a host Linux, Windows or MAC over USB, Ethernet or Serial.  

DATA TYPES

The library makes use of C structures and typedefs to promote portability, and is known to run on various GNU/Linux distributions, macOS, Windows, and mbed (via tiny-iiod). The main C structures are:
iio_scan_context
The scanning context
iio_context_info
The information related to a discovered context
iio_context
Contains the representation of an IIO context
iio_device
Represents a device in the IIO context
iio_channel
Represents an input or output channel of a device
iio_buffer
An input or output buffer, used to read or write samples
iio_data_format
Contains the format of a data sample.

 

LIST OF ROUTINES

The following routines are part of the library. Consult the Doxygen pages for details on their operation (in the SEE ALSO section).

Scan Functions for scanning available contexts

Function
Description
iio_create_scan_context
Create a scan context
iio_scan_context_destroy
Destroy the given scan context
iio_scan_context_get_info_list
Enumerate available contexts
iio_context_info_list_free
Free a context info list
iio_context_info_get_description
Get a description of a discovered context
iio_context_info_get_uri
Get the URI of a discovered context
iio_create_scan_block
Create a scan block
iio_scan_block_destroy
Destroy the given scan block
iio_scan_block_scan
Enumerate available contexts via scan block
iio_scan_block_get_info
Get the iio_context_info for a particular context

TopLevel Top-level functions

Function
Description
iio_library_get_version
Get the version of the libiio library
iio_strerror
Get a string description of an error code
iio_has_backend
Check if the specified backend is available
iio_get_backends_count
Get the number of available backends
iio_get_backend
Retrieve the name of a given backend

Context Context

Function
Description
iio_create_default_context
Create a context from local or remote IIO devices
iio_create_local_context
Create a context from local IIO devices (Linux only)
iio_create_xml_context
Create a context from XML data in memory
iio_create_xml_context_mem
Create a context from XML data in memory
iio_create_network_context
Create a context from the network
iio_create_context_from_uri
Create a context from a URI description
iio_context_clone
Duplicate a pre-existing IIO context
iio_context_destroy
Destroy the given context
iio_context_get_version
Get the version of the backend in use
iio_context_get_xml
Obtain a XML representation of the given context
iio_context_get_name
Get the name of the given context
iio_context_get_description
Get a description of the given context
iio_context_get_attrs_count
Get the number of context-specific attributes
iio_context_get_attr
Retrieve the value of a context-specific attribute
iio_context_get_attr_value
Retrieve the value of a context-specific attribute
iio_context_get_devices_count
Enumerate the devices found in the given context
iio_context_get_device
Get the device present at the given index
iio_context_find_device
Try to find a device structure by its name of ID
iio_context_set_timeout
Set a timeout for I/O operations

Device Device

Function
Description
iio_device_get_context
Retrieve a pointer to the iio_context structure
iio_device_get_id
Retrieve the device ID
iio_device_get_name
Retrieve the device name
iio_device_get_channels_count
Enumerate the channels of the given device
iio_device_get_attrs_count
Enumerate the device-specific attributes of the given device
iio_device_get_buffer_attrs_count
Enumerate the buffer-specific attributes of the given device
iio_device_get_channel
Get the channel present at the given index
iio_device_get_attr
Get the device-specific attribute present at the given index
iio_device_get_buffer_attr
Get the buffer-specific attribute present at the given index
iio_device_find_channel
Try to find a channel structure by its name of ID
iio_device_find_attr
Try to find a device-specific attribute by its name
iio_device_find_buffer_attr
Try to find a buffer-specific attribute by its name
iio_device_attr_read
Read the content of the given device-specific attribute
iio_device_attr_read_all
Read the content of all device-specific attributes
iio_device_attr_read_bool
Read the content of the given device-specific attribute
iio_device_attr_read_longlong
Read the content of the given device-specific attribute
iio_device_attr_read_double
Read the content of the given device-specific attribute
iio_device_attr_write
Set the value of the given device-specific attribute
iio_device_attr_write_raw
Set the value of the given device-specific attribute
iio_device_attr_write_all
Set the values of all device-specific attributes
iio_device_attr_write_bool
Set the value of the given device-specific attribute
iio_device_attr_write_longlong
Set the value of the given device-specific attribute
iio_device_attr_write_double
Set the value of the given device-specific attribute
iio_device_buffer_attr_read
Read the content of the given buffer-specific attribute
iio_device_buffer_attr_read_all
Read the content of all buffer-specific attributes
iio_device_buffer_attr_read_bool
Read the content of the given buffer-specific attribute
iio_device_buffer_attr_read_longlong
Read the content of the given buffer-specific attribute
iio_device_buffer_attr_read_double
Read the content of the given buffer-specific attribute
iio_device_buffer_attr_write
Set the value of the given buffer-specific attribute
iio_device_buffer_attr_write_raw
Set the value of the given buffer-specific attribute
iio_device_buffer_attr_write_all
Set the values of all buffer-specific attributes
iio_device_buffer_attr_write_bool
Set the value of the given buffer-specific attribute
iio_device_buffer_attr_write_longlong
Set the value of the given buffer-specific attribute
iio_device_buffer_attr_write_double
Set the value of the given buffer-specific attribute
iio_device_set_data
Associate a pointer to an iio_device structure
iio_device_get_data
Retrieve a previously associated pointer of an iio_device structure
iio_device_get_trigger
Retrieve the trigger of a given device
iio_device_set_trigger
Associate a trigger to a given device
iio_device_is_trigger
Return True if the given device is a trigger
iio_device_set_kernel_buffers_count
Configure the number of kernel buffers for a device

Channel Channel

Function
Description
iio_channel_get_device
Retrieve a pointer to the iio_device structure
iio_channel_get_id
Retrieve the channel ID
iio_channel_get_name
Retrieve the channel name
iio_channel_is_output
Return True if the given channel is an output channel
iio_channel_is_scan_element
Return True if the given channel is a scan element
iio_channel_get_attrs_count
Enumerate the channel-specific attributes of the given channel
iio_channel_get_attr
Get the channel-specific attribute present at the given index
iio_channel_find_attr
Try to find a channel-specific attribute by its name
iio_channel_attr_get_filename
Retrieve the filename of an attribute
iio_channel_attr_read
Read the content of the given channel-specific attribute
iio_channel_attr_read_all
Read the content of all channel-specific attributes
iio_channel_attr_read_bool
Read the content of the given channel-specific attribute
iio_channel_attr_read_longlong
Read the content of the given channel-specific attribute
iio_channel_attr_read_double
Read the content of the given channel-specific attribute
iio_channel_attr_write
Set the value of the given channel-specific attribute
iio_channel_attr_write_raw
Set the value of the given channel-specific attribute
iio_channel_attr_write_all
Set the values of all channel-specific attributes
iio_channel_attr_write_bool
Set the value of the given channel-specific attribute
iio_channel_attr_write_longlong
Set the value of the given channel-specific attribute
iio_channel_attr_write_double
Set the value of the given channel-specific attribute
iio_channel_enable
Enable the given channel
iio_channel_disable
Disable the given channel
iio_channel_is_enabled
Returns True if the channel is enabled
iio_channel_read_raw
Demultiplex the samples of a given channel
iio_channel_read
Demultiplex and convert the samples of a given channel
iio_channel_write_raw
Multiplex the samples of a given channel
iio_channel_write
Convert and multiplex the samples of a given channel
iio_channel_set_data
Associate a pointer to an iio_channel structure
iio_channel_get_data
Get a pointer to a channel's data format structure
iio_channel_get_type
Get the type of the given channel
iio_channel_get_modifier
Get the modifier type of the given channel

Buffer Buffer

Function
Description
iio_buffer_get_device
Retrieve a pointer to the iio_device structure
iio_device_create_buffer
Create an input or output buffer associated to the given device
iio_buffer_destroy
Destroy the given buffer
iio_buffer_get_poll_fd
Get a pollable file descriptor
iio_buffer_set_blocking_mode
Make iio_buffer_refill() and iio_buffer_push() blocking or not
iio_buffer_refill
Cancel all buffer operations
iio_buffer_push
Cancel all buffer operations
iio_buffer_push_partial
Send a given number of samples to the hardware
iio_buffer_cancel
Cancel all buffer operations
iio_buffer_start
Get the start address of the buffer
iio_buffer_first
Find the first sample of a channel in a buffer
iio_buffer_step
Get the step size between two samples of one channel
iio_buffer_end
Get the address that follows the last sample in a buffer
iio_buffer_foreach_sample
Call the supplied callback for each sample found in a buffer
iio_buffer_set_data
Associate a pointer to an iio_buffer structure
iio_buffer_get_data
Retrieve a previously associated pointer of an iio_buffer structure

Debug Debug and low-level functions

Function
Description
iio_device_get_sample_size
Get the current sample size
iio_channel_get_index
Get the index of the given channel
iio_channel_get_data_format
Get a pointer to a channel's data format structure
iio_channel_convert
Convert the sample from host format to hardware format
iio_channel_convert_inverse
Convert the sample from host format to hardware format
iio_device_get_debug_attrs_count
Enumerate the debug attributes of the given device
iio_device_get_debug_attr
Get the debug attribute present at the given index
iio_device_find_debug_attr
Try to find a debug attribute by its name
iio_device_debug_attr_read
Read the content of the given debug attribute
iio_device_debug_attr_read_all
Read the content of all debug attributes
iio_device_debug_attr_write
Set the value of the given debug attribute
iio_device_debug_attr_write_raw
Set the value of the given debug attribute
iio_device_debug_attr_write_all
Set the values of all debug attributes
iio_device_debug_attr_read_bool
Read the content of the given debug attribute
iio_device_debug_attr_read_longlong
Read the content of the given debug attribute
iio_device_debug_attr_read_double
Read the content of the given debug attribute
iio_device_debug_attr_write_bool
Set the value of the given debug attribute
iio_device_debug_attr_write_longlong
Set the value of the given debug attribute
iio_device_debug_attr_write_double
Set the value of the given debug attribute
iio_device_identify_filename
Identify the channel or debug attribute corresponding to a filename
iio_device_reg_write
Set the value of a hardware register
iio_device_reg_read
Get the value of a hardware register

 

DIAGNOSTICS

All error codes are returned as negative number return codes. In these cases, the value can be passed to the iio_strerror routine.  

SEE ALSO

iio_attr(1), iio_info(1), iio_readdev(1), iio_writedev(1), iio_reg(1)

libiio home page:
https://wiki.analog.com/resources/tools-software/linux-software/libiio

libiio code:
https://github.com/analogdevicesinc/libiio

Doxygen for libiio:
https://analogdevicesinc.github.io/libiio/

Kernel Doc:
https://www.kernel.org/doc/html/latest/driver-api/iio/index.html https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio  

BUGS

All bugs are tracked at: https://github.com/analogdevicesinc/libiio/issues  

LICENSE

The libiio source code and resulting binaries (libraries) are released and distributed under the GNU Lesser General Public License, v2.1 or (at your option) any later version.
The libiio test and example application(s) source code and resulting binaries (executables) are released and distributed under the GNU General Public License, v2.0 or (at your option) any later version.
The libiio man pages are released and distributed under the Creative Commons Attribution-ShareAlike 4.0 International Public License.


 

Index

NAME
SYNOPSIS
OPTIONS
DESCRIPTION
DATA TYPES
LIST OF ROUTINES
DIAGNOSTICS
SEE ALSO
BUGS
LICENSE

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Time: 07:03:18 GMT, June 19, 2020